Phenylenediacetate ester



able for use as lubricating oils are Patented Oct. 2, 1951 PHENYLENEDIACETATE ESTER Paul V. Smith, J r., Westficld, and Fred Knoth, Jr.,

Union, N. J., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application December 29, 1948, Serial No. 68,084

3 Claims.

This invention relates to a new class of compounds which have been found to be particularly suitable for use as synthetic lubricants because of their high viscosity indices and high load carrying capacity.

In the lubricant art, considerable progress has been realized in recent years in the production of lubricants characterized by one or more specific properties and adapted for particular uses. In the main, this progress can be attributed to two developments: the first, new refining procedures, and the second, addition agents capable of imparting particular properties to available lubricants. Thus, viscosity index improvers and pour point depressants are added to automotive lubricants to render the lubricants more adaptable to wide changes in temperature conditions, while other agents are added to improve the load carrying properties of a lubricant which is to be employed, for example, under extreme pressure conditions.

points, and higher flash points than mineral oils of corresponding viscosity. The esters described in the present specification have been found to exhibit high viscosity indices and high load carrying capacity. Those esters which do not exhibit a pour point which is sufiiciently low for use without additive may be made useful by simply adding a pour point depressant, as in the case of mineral oils. The esters possessing both high viscosity indices and low pour points are of special value in the lubrication of engines which are subjected to high temperatures such as combustion turbine engines, particularly those of the "prop-jet type.

The new compounds of the present invention which have been found to be particularly suitaralkyl esters of the formula )CHMCOOR Ar where Ar is an aromatic nucleus which may be a.

2 a the total number of carbon atoms in all of the side chains, however, being not greater than where n and n are integers from. 1 to 9; and Where R and R. are aliphatic hydrocarbon radicals, saturated or unsaturated, straightchain or branched, or radicals consisting of a series of saturated aliphatic hydrocarbon radicals linked through 1 to 5 atoms of oxygen and/or sulfur in each group, the number of sulfur atoms in each group being not greater than 2, and each pair of oxygen and/or sulfur atoms being separated by a chain of at least two carbon atoms with at least two carbon atoms between the carboxyl group and the first oxygen or sulfur atom in the .ester group, the total number of carbon, oxygen and sulfur atoms in the two ester groups being from 8 to 40. The two carboxyalkyl groupsmay be joined to the aromatic nucleus in any relative positions, and mixtures of esters may be employed in which the carboxyalkyl groups are joined in various positions, as in the case of derivatives of mixtures of two or more: of the isomeric xylenes. Esters in which the R and R groups are of branched chain structure are especially desirable, since branching in these groups tends to give a compound of low pour point.

The esterification process can be carried out by the usual methods, preferably employing an esterification catalyst, such as p-toluene sulfonic acid, and a water entraining agent. The dibasic acids from which esters of the present invention are derived may be prepared by chlorinating an alkylaromatic hydrocarbon or by chloralkylating an aromatic hydrocarbon to introduce two chloralkyl groups, then converting the chlorinated compound into. a nitrile, and hydrolyzing the latter. Thus, a xylene may be converted into a phenylenediacetic acid by chlorination, followed by the steps outlined above; or a cli(chloromethyDbenzene may be formed by two successive treatments of benzene with formaldehyde and hydrogen chloride; or a di(chloromethyl) benzene may be formed by first chlorinating toluene to give benzyl chloride and following this by a single chlormethylation step. Dibasic acids of this type may also be prepared by condensing 2 mols of a dibasic acid anhydride or 2 mols of a dibasic acid monoacyl chloride with the aromatic compound in the presence of a Friedel-Crafts catalyst, followed by reduction of the carbonyl groups to methylene groups. Illustrative examples of the dibasic acids which may be employed in the synthesis of the esters of the'present invention are the following:

m-Phenylenediacetic acid p-Phenylenediacetic acid and illustrative examples are typified by the 7 following Methyl alcohol Ethyl alcohol n-Propyl alcohol n Butyl alcohol Isobutyl alcohol n-Amyl alcohol Isoamyl alcohol n-Octyl alcohol Z-ethylhexyl alcohol 'Cetyl alcohol Oleyl alcohol Ethylene glycol mono-n-butyl ether Ethylene glycol mono-Z-ethylbutyl ether Ethylene glycol mono-Z-ethylhexyl ether Ethylene-glycol monoisooctyl ether p-n-Butylmercaptoethanol sa-Tert.-octylmercaptoethanol ,B-n-Dodecylmercaptoethanol Diethylene glycolmono-n-butyl ether Diethyleneglycol mono-2-ethylbutyl ether Diethylene glycol mono-Z-ethylhexyl ether Propylene glycol mono-butyl thioether Propylene glycol -mono-tert.-octyl thioether Propylene glycol mono-n-dodecyl thioether n-Butylmercaptoethoxyethanol Tert.-octylmercaptoethoxyethanol n-Dodecylmercaptoethoxyethanol n-Butylmercaptopropoxypropanol Tert, -octylmercaptopropoxypropanol n-Dodecylmercaptopropoxypropanol Propylene glycol mono-n-butyl ether Dipropylene glycol monomethyl ether Dipropylene glycol monoethyl ether Dipropylene glycol mono-n-butyl ether Tripropylene glycol monomethyl ether Tripropylene glycol monoethyl ether Tripropyleneglycol mono-n-butyl ether Propylene glycol monoisopropyl ether Dipropylene glycol monoisopropyl ether Tripropylene glycol .monoisopropyl ether 'Many of the above listed ether alcohols, formed by the reaction of ethylene oxide or propylene oxide with aliphatic alcohols, are known in the industry as Dowanols, Carbitols, or Cellosolves.

Agroup of alcohols especially adapted for use in connection with the present invention are the so-called "Oxo alcohols, prepared by thereaction of carbon monoxide and hydrogen upon the olefins obtainable from petroleum products and hydrogenation of the resulting'aldehydes. Materials such as diisobutylene and C7 olefins are especially suitable for this purpose; also higher molecular weight olefinic materials are sometimes employed. The alcohols obtained in this manner are primary alcohols and normally have a branched chain structure.

For the production of esters having low pour points it is advantageous to employ branched chain alcohols, such as those derived by the 0x0 process described above.

7 In'the'ltable below will be shown data obtained 'in tests of the properties'of two typical esters illustrating the present invention. The di-ndecyl m-phenylene diacetate was prepared as follows:

A mixture was prepared consisting of 34.3 grams (0.7 mol) of sodium cyanide and 400 ml. of '75 aqueous ethanol, and to this mixture while being agitated at refluxing temperature was added gradually grams (0.303 mol) of m-xylylene dibromide. The hot solution was filtered and added to 900 ml. of water and the wholewas extracted with ether, after which the ether was evaporated yielding 42.7 grams (90.5%) of prodnot, which was m-Xylylene dinitrile. This was hydrolized to the dibasic acid by refluxing with a mixture'of 280ml. of concentrated sulfuric acid and loo-ml. water per mol of dinitrile. The solid acid precipitated from the aqueous solution upon the addition of 750 ml. of ice water.

The acid'prepared above was esterified by the following method: In a 1-liter round bottomed reaction flask, fitted with a reflux condenser and a water trap, was placed a charge consisting of one mol of .a dibasic acid, two mols of n-decanol, 4.5 grams of .p-tol-uene 'sulfonic acid monohydrate,-and ml. of toluene. The mixture was refluxed until no more water collected inthe trap. The resulting solution was washed with three 100 ml. portions of saturated aqueous sodium carbonate-solutionand one 100 ml. portion of. water. After drying over Drierite (an-hydrous calcium-sulfate) the. material was filtered and stripped to a bath temperature of ZOO-225 C. at a pressureof about 5mm.v

The di-n-decyl p-phenylene diacetate wasprepared as follows: To a mixture of 253 grams (2 mols) benzyl chloride and '70 grams (-2 .3 m01s) paraformaldehyde'was added 70 grams of pulverized zinc chloride and hydrogen chloride was bubbled in for a period of four hours while the temperature was kept below 60 C. The .product was decanted, and benzene was added to the reaction flask to Wash out the remaining traces of the product; the total product including the benzene washings was washed with water and filtered to remove'solid material. The product was further washed with dilute sodium carbonate solution and water. The product, consisting'oi p-xylylene dichloride dissolved in benzene, was treated with sodium cyanide as in the case of m-xylylene dibromide and then hydrolyzed to form the corresponding dibasic acid. This acid was :esterified with n-decanol by the method described above.

1\flllnlllen Ester E33 2 $3 1; 555: Viscosity, Viscosity Weights e Q 0 210 F. Index Carried (Gradual Loading) Di-n-decyl,m-diphenylenediacetate '30- 25.510 5.025 "136 2 Di-n-decyl, p-pheny1enediacetate L--- 415 35 -7 2 153 15 The above data indicate that the esters constituting the subject matter of the present invention possess characteristics, particularly with regard to viscosity index and load carrying capacity, which indicate clearly their suitability for general use as lubricating oils. Th esters of the present invention may also be blended with mineral lubricating oils to give lubricants of improved viscosity index and. load carrying capacity.

What is claimed is: 1. As a new composition of matter di-n-decyl phenylenediacetate.

2. As a new composition of matter di-n-decyl m-phenylenediacetate.

3. As a new composition of matter .di-n-decyl p-phenylenediacetate.

PAUL V. SMITH, JR. FRED KNOTH, JR.

6 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Titley: J. Chem. Soc., 1928, pp. 2571-2583. 

1. AS A NEW COMPOSITION OF MATTER DI-N-DECYL PHENYLENEDIACETATE. 